Passerina caerulea sub species

Subspecies of Blue Grosbeak and its potential use for Motus tags

This is an evaluation of the sub-species of Blue Grosbeak (Passerina caerulea) and its potential use as model species for Oaxacan Central Valleys. Most information comes from Birds Of the World https://birdsoftheworld.org/bow/species/blugrb1/cur/introduction and the publication from Storer and Zimmerman (1959) https://deepblue.lib.umich.edu/items/24824b17-6f43-4b56-9ad8-64da66786885.

Currently, 6 sub-species have been recognized, their infromation about morphometrics and distribution is summarized on this table:

Sub especie	Region	Breeding	Wintering	Wing length mean (mm)	Wing length range	Tail length mean	Tail length range	Culmen length mean	Culmen length range	Body mass mean	Body mas range
caerulea	Eastern North America	Nebraska, Pensilvania, Texas, South Carolina	Greater antilles, E & S México, Panama	88.36000	85 - 92	66.75333	63-73.5	12.44333	11.3 - 13.7	NA	NA
interfusa	Western North America and México	Nevada, Colorado, Sonora, Chihuahua	Sonora, Jalisco and Valley of México	89.70667	86.5 - 94	69.58667	66 - 75	12.24000	11.1 - 14	NA	NA
salicaria	Californias	California and Baja California	Baja California Sur	90.35000	88 - 94	71.00000	68 - 74.5	11.16000	10 - 11.8	NA	NA
eurhyncha	México	México, Guanajuato, SLP, Northern? Oaxaca	NA	94.17400	90 - 96	74.37000	70 - 80	12.94800	12.1 - 13.7	NA	NA
eurhyncha	Oaxaca (n = 2)	Oaxaca (9 and 20mi Southeast Oaxaca)	NA	95.50000	95-96	75.00000	74 - 76	13.30000	12.9 - 13.7	NA	NA
chiapanensis	Chiapas (n = 7)	Chiapas	NA	95.90000	93.5 - 98.5	76.60000	73 - 81	14.80000	14.5 - 15.1	NA	NA
lazula	Central America	El Salvador, Costa Rica	NA	91.11000	87.5 - 93	73.33000	68.5 - 77	14.09000	12.7 - 15.1	NA	NA

From these species, 2 or maybe 3 could be found in Oaxaca. These are caerulea, interfusa and eurhyncha.

Sub especie	Region	Breeding	Wintering	Wing length mean (mm)	Wing length range	Tail length mean	Tail length range	Culmen length mean	Culmen length range	Body mass mean	Body mas range
caerulea	Eastern North America	Nebraska, Pensilvania, Texas, South Carolina	Greater antilles, E & S México, Panama	88.36000	85 - 92	66.75333	63-73.5	12.44333	11.3 - 13.7	NA	NA
interfusa	Western North America and México	Nevada, Colorado, Sonora, Chihuahua	Sonora, Jalisco and Valley of México	89.70667	86.5 - 94	69.58667	66 - 75	12.24000	11.1 - 14	NA	NA
eurhyncha	México	México, Guanajuato, SLP, Northern? Oaxaca	NA	94.17400	90 - 96	74.37000	70 - 80	12.94800	12.1 - 13.7	NA	NA
eurhyncha	Oaxaca (n = 2)	Oaxaca (9 and 20mi Southeast Oaxaca)	NA	95.50000	95-96	75.00000	74 - 76	13.30000	12.9 - 13.7	NA	NA

Based on measurements we could tell appart individuals(?)

But the distribution of interfusa and eurhyncha for Oaxacan Central Valleys do not seem to overlap…

What does ebird say?

Blue Grosbeaks in Oaxaca

To evaluate the status and trends in detail I requested a status and trends passcode

“Tu clave de estatus y tendencias:

4inq4qjs1326”

Status and trends of Oaxaca Central Valley seem to show there are not a lot of migration happening on the Central Valleys (?):

But there are changes on relative abundances happening throughout the Central Valleys. Whether is because of individuals of interfusa arriving from México and the US of individuals of eurhyncha conducting local movements, we do not know.

BLUE GROSBEAKS AUDIOS

Here is information from the Macaulay library. I selected audios from each locality between June and August. All songs selected include at least 2 trill elements

NOTE: subspecie caerulea and and interfusa had longer songs than eurhyncha but were not included in these comparisons

The information of the audios goes as follows:

OAX (eurhyncha)

ML640535448

ML622186110

ML255479461

ML636797365

NEW MEX, COLORADO(interfusa)

ML550323781

ML562328101

ML67756551

ML465652321

PEN, SOUTH CAROLINA (caerulea)

ML621600823

ML621003816

ML248063861

ML350040061